A new Ir(III)-NHC catalyst is reported that shows remarkable activity in the N-alkylation of unprotected amino acids. The catalytic system gives excellent selectivity toward monoalkylated α-amino acids and a high degree retention stereochemistry. wide range nonnatural have been prepared. These compounds represent an array building blocks could be used for direct synthesis peptidomimetics. amino...

A Simple and efficient method for synthesis of tetrahydropyrimido[4,5-b]quinoline derivatives via three component reaction of aromatic aldehydes, dimedone and 6-amino uracil derivatives using a catalytic amount of sulfonic acid functionalized nanoporous silica (SBA-15-Pr-SO3H) is described. The advantages of this method are easy and clean work-up, high yield, mild reaction c...

1,5-Diaminotetrazole can be nitrated under very mild conditions by using nitronium tetrafluoroborate to result in 5-amino-1-nitriminotetrazole (1) in good yields. The same reaction can be performed with 1-amino-5-amino-4-methyltetrazole to yield 5-amino-4-methyl-1-nitriminotetrazole (2). Both compounds have been isolated and completely characterized by using vibrational spectroscopy, mass spect...

The flavor of dry cured ham explains the high appreciation of this product and it determines consumer acceptance. Volatile compounds provide valuable information about the odor and sensory quality of dry cured hams. Since amino acids are the origin of some volatile compounds of dry cured ham, the volatile and amino acid compositions of forty-one dry cured hams from Spain and France were determi...

BACKGROUND The authors are aware of only one article investigating amino acid concentrations in cerebrospinal fluid (CSF) in patients with ruptured intracranial aneurysms, and this was published 31 years ago. Since then, both management of subarachnoid haemorrhage (SAH) and amino acid assay techniques have seen radical alterations, yet the pathophysiology of SAH remains unclear. OBJECTIVE To ...

The unique aroma of melons (Cucumis melo L., Cucurbitaceae) is composed of many volatile compounds biosynthetically derived from fatty acids, carotenoids, amino acids, and terpenes. Although amino acids are known precursors of aroma compounds in the plant kingdom, the initial steps in the catabolism of amino acids into aroma volatiles have received little attention. Incubation of melon fruit cu...

BACKGROUND Biuret assays for total protein measurement are considered to react with all peptides longer than 2 residues. Some studies using biuret assays of urine suggest that small peptides generally are more abundant than proteins in urine, but it is not clear whether this is a problem of assay specificity. METHODS We analyzed the specificity and kinetics of a biuret reaction for solutions ...

The plant hormone jasmonic acid (JA) and its derivative, an amino conjugate of JA (jasmonoyl isoleucine: JA-Ile), are signaling compounds involved in the regulation cellular defense development plants [...]

A series of novel 2-benzylamino-3-substituted quinazolin-4(3H)-ones have been synthesized by treating 3-amino-2-benzylamino quinazolin-4(3H)-one, with different aldehydes and ketones. The starting material 3-amino-2-benzylamino quinazolin-4(3H)-one was synthesized by nucleophilic substitution of thiomethyl group of 3-amino-2-methylthio quinazolin-4(3H)-one by benzylamine. The title compounds we...